Subject: [Megaco] Bypass(hairpin?) TDM SS7 signal channel

From: "변동우"<[email-masked]>
Date: Fri, 28 May 2004 10:04:07 +0900

Hi everyone,

I'm trying to use the Trunk Gateway with E1
port.

I want to use E1 trunk which has 30 PCM bearer
channels and 1 SS7 signal channel. Those bearer channels would be connected wiht
Physical Termination, and signal channel should be bypassed to another E1
link.

The configuration is as below.

+-----------+      E1
+------------------+    E1
+-----------+
| SS7
|---------------| Port1      Port2 |-----------|
SS7       |
| OPC H'100 |
bearer 30ch
|        MG
|  SS7 1ch  | OPC H'200 |
| DPC H'200 |
SS7     1ch
|
|           | DPC H'100
|

+-----------+
+------------------+
+-----------+

MG should not do anything about signal channel except
bypassing.

I think it may hairpin, so I made message as below, but didn't
work.

MEGACO/1 [$MGC_IP]:2944 Transaction = $TRANSACTION { Context = $ { Add =
brtkt0c16 { Media { Stream = 1 { LocalControl { Mode = SendReceive, tdmc/gain=2,
tdmc/ec=on} } } }, Add = brtkt1c16 { Media { Stream = 1 { LocalControl { Mode =
SendReceive, tdmc/gain=2, tdmc/ec=on} } } } } }

Anyone know how to make hairpin or bypass of TDM SS7 signalling
channel?

I'll appreciate if you reply.

Regards,

Dongwoo Byun.

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---

From: [email-masked]
Date: Fri, 28 May 2004 14:19:28 +0200

Hi Dongwoo,

"TDM hairpinning" of a SS7 MTP2 connection (on DS0 level), - according your
configuration -, requires the bearer service capability "1x64-kbit/s
Unrestricted Digital Information (UDI)".

Note: in your scenario are Signal Processing functions (Gain Control, EC)
activated, which doesn't make sense, or is even not allowed ("because it's
generating bit failures, thus , a bit error rate of zero may not guaranteed
by your MG"). Technically, you may bypass your DSP device MG-internally for
such specific TDM-to-TDM connections. Or, if you are looping in a DSP, then
the DSP channel settings must guarantee "UDI capability" (this specific DSP
operation mode is also called as "transparent channel", "clear mode", or
"clear channel data").

The H.248 Context has 2 TDM Termination. The TDM Bearer Capability is
defined in Annex C.9: "TMR = 64 kbit/s unrestricted".

Exactly this topic was discussed under following subject some weeks ago:

"Signaling of UDI rsp Clearmode Bearer Service; Re: TDM Hairpinning;Re:
[Megaco] Hairpin case A/u Law conversion"

See for instance:
http://www1.ietf.org/mail-archive/web/megaco/current/msg05095.html
http://www1.ietf.org/mail-archive/working-groups/megaco/current/msg05068.html

http://www1.ietf.org/mail-archive/working-groups/megaco/current/msg05069.html

=> in case of binary encoding mode, see H.248.1 Annex C
=> in case of text encoding mode, see the outcome of recent ITU-T meeting:
http://www1.ietf.org/mail-archive/web/megaco/current/msg05140.html

Hope this helps,
regards,
Albrecht

ALCATEL

                      "변동우"                                                                                                                      
                      <[email-masked]         To:      [email-masked]                                                                             
                      >                        cc:                                                                                                  
                      Sent by:                 Subject: [Megaco] Bypass(hairpin?) TDM SS7 signal channel                                            
                      megaco-bounces@i                                                                                                              
                      etf.org                                                                                                                       

                      28.05.2004 03:04                                                                                                              

Hi everyone,

I'm trying to use the Trunk Gateway with E1 port.

I want to use E1 trunk which has 30 PCM bearer channels and 1 SS7 signal
channel. Those bearer channels would be connected wiht Physical
Termination, and signal channel should be bypassed to another E1 link.

   +-----------+      E1       +------------------+    E1     +-----------+
   | SS7       |---------------| Port1      Port2 |-----------| SS7       |
   | OPC H'100 |  bearer 30ch  |        MG        |  SS7 1ch  | OPC H'200 |
   | DPC H'200 |  SS7     1ch  |                  |           | DPC H'100 |
   +-----------+               +------------------+           +-----------+

MG should not do anything about signal channel except bypassing.

I think it may hairpin, so I made message as below, but didn't work.

MEGACO/1 [$MGC_IP]:2944 Transaction = $TRANSACTION { Context = $ { Add =
brtkt0c16 { Media { Stream = 1 { LocalControl { Mode = SendReceive,
tdmc/gain=2, tdmc/ec=on} } } }, Add = brtkt1c16 { Media { Stream = 1 {
LocalControl { Mode = SendReceive, tdmc/gain=2, tdmc/ec=on} } } } } }

Anyone know how to make hairpin or bypass of TDM SS7 signalling channel?

Regards,

Dongwoo Byun.

Megaco mailing list
[email-masked]